The Sun is the main driver of climate change. Not you. Not carbon dioxide.

Debates between those who claim humans are causing catastrophic global warming and those who dissent from this thesis often include questions related to whether technologies that today are immature or limited in commercial use will be much more quickly disseminated in future. For example, the advocates of the catastrophe theory argue that the world’s transport sector soon will be radically transformed through the rapid dissemination of electric vehicles (EVs), generally including electric hybrids (PHEVs) and all-electric cars (BEVs).

Typically, in debates of this nature, the dissenting side points to statistics concerning actual consumer purchases in the past. Catastrophe theorists brush that aside by pointing to ever more optimistic claims by technology marketers and government agencies committed to reducing greenhouse gas emissions by the extensive use of “policy measures” (i.e. massive subsidies and product mandates). For further “evidence”, they point to the rapid penetration of computer and information technologies as a model and the significant growth in percentage sales (from very low levels) that have characterized EVs over the past decade. As the debate is about the future, neither side can prove its thesis.

In these circumstances, it would seem useful to at least establish a scorecard, or basis for determining statistically whether the sales of EVs are increasing at rates that justify the “optimistic” or “pessimistic” views.

Where are we now? According to the International Energy Agency (IEA), there were 1.25 million electric cars on the world’s roads at the end of 2015. 80% of the electric cars in the world are located in the United States, China, Japan, the Netherlands and Norway. Consumer acceptance of EVs, while growing, remains quite low; EVs constituted 1% or more of new vehicles sales in 2015 in only seven countries: Norway, the Netherlands, Sweden, Denmark, France, China and the United Kingdom. In all these countries, large taxpayer subsidies (e.g. up to $7,500 per vehicle in the U.S.) provide the incentive to increase purchases. Today, EVs account for a negligible share (0.1%) of the global stock of personal and commercial vehicles.

What is the “policy” goal in terms of future sales? There is no single answer to this question. The IEA has established a process called Energy Technology Perspectives (ETP) that seeks to define the objectives and the technology “roadmaps” that would achieve emissions reductions consistent with the objectives of the OECD countries. The IEA Vision is one in which global greenhouse gas (GHG) emissions will fall from 33 gigatonnes (Gt) in 2013 to about 15 Gt in 2050 and continue to fall after that. This (allegedly) would be consistent with the goal of maintaining the rise in global average temperatures at 2 degrees C. or less from pre-industrial levels. Today, the transport sector accounts for about 23% of global GHG emissions. The ETP 2DS scenario that the IEA uses as a basis for analysis foresees the transport sector accounting for 18% of the GHG emissions reductions needed to meet the IEA Vision. EVs are projected to constitute significantly to this objective. Specifically, the ETP 2DS foresees EVs constituting 150 million (10%) of the total light duty vehicle stock by 2030 and nearly 1 billion (40%) of the total light duty vehicle stock by 2050.

In 2009, several governments (including Canada) formed a multilateral policy forum called the Electric Vehicle Initiative (EVI) to accelerate the deployment of EVs worldwide. The goal of this group is the global deployment of 20 million EVs by 2020. The Paris Declaration on Electro-Mobility and Climate Change was announced (with virtually no fanfare or media coverage) at COP21 in Paris in December 2015. The declaration sets targets of more than 400 million electric two-wheelers and more than 100 million EVs by 2030.

Other “expert” organizations have weighed in with their educated guesses as to how many EVs will be on the roads by 2020. Bloomberg Business News (almost always optimistic about the ease of attaining GHG emission reduction goals) projects 7.4 million. Adam Whitmore, a prominent independent expert who strongly favours EVs, projects somewhere between 7.8 to 13 million vehicles. OPEC, in its oil market analysis, projects only 1.7 million. British Petroleum, in its usually well-regarded February 2016 global energy forecast to 2040, foresaw almost no significant uptake of EVs until at least 2035. These projections are based on different assumptions as to whether governments will continue the current high level of taxpayer subsidies. According to the current U.S. program subsidies will end after 200,000 EVs are sold there. Other important assumptions concern the rates at which new battery technologies can be developed and commercialized, future vehicle prices and the rate at which sales will grow from current levels.

This provides at least a range of estimates that one might use as a way of measuring whether EVs are on track to meet the goals claimed by their advocates. By 2020, if the global inventory of EVs is three million or less, it will demonstrate conclusively that the technology is facing serious market barriers that may limit its role in reducing GHG emissions for decades. Continuation of the present relatively fast rate of growth in sales plus some acceleration could yield a global stock of 7.4 to 13 million EVs by 2020. While this would be impressive, it would still be an afterthought in a global vehicle population of about 1.3 billion. A 2020 EV population of 20 million (i.e. a 1600% increase from present levels) would match with current policy aspirations. By 2030, the COP21 and IEA policy prescriptions are for 100 million to 150 million EVs on the roads, a quite remarkable range of goals for only 14 years from now. This would be evidence that EVs had largely overcome the initial market barriers and were potentially on a path to becoming a large share of the vehicle stock. Still, at 150 million, EVs would only constitute 10% of the global vehicle stock; 1.35 billion vehicles would still be oil-fueled. If the IEA ETP scenario were to be attained, by 2050, (i.e. 34 years from now), EVs would come close to parity with oil-fueled vehicles in new car sales, but they would still represent only 40% of the global vehicle stock.

We are asked to believe that these goals will be achieved during a period of time when lower oil prices and continuing improvements in the technology of internal combustion engines are making oil-fueled vehicles ever more competitive. No target set by western governments for the expansion of the EV fleet has yet been met.

However, there is a first time for everything. With the figures set out in the preceding paragraphs, we have a yardstick we can use in future to debate the validity of the projections.